Yahoo (NASDAQ: YHOO) has inked a deal to expand distribution of its Web search services on personal computers via a pact with software-packaging firm Acresso Software, the companies said on Thursday.

Acresso, which was recently spun off by entertainment media security company Macrovision (NASDAQ: MVSN), makes the widely used InstallShield, a technology used by software makers and corporate network administrators to install new PC programs.

Under the deal, Acresso plans to distribute the Yahoo Toolbar to its customer base of more than 500 million computer users. The toolbar, a free add-on users download to browsers, provides access to search and other Web navigation services from Yahoo.

The deal is designed to keep Yahoo from losing share in the competitive Web search market. Yahoo makes most of its money running ads alongside Web search and other services it offers.

Rival Google (NASDAQ: GOOG) the dominant Web search provider, has struck a succession of similar distribution deals for its own toolbar with partners ranging from software maker Adobe Systems (NASDAQ: ADBE) to PC maker Dell (NASDAQ: DELL) to social network MySpace.

Microsoft (NASDAQ: MSFT), No. 3 in U.S. Web search after Yahoo, this week displaced Yahoo in a deal with Hewlett-Packard (NYSE: HPQ) to distribute Microsoft search services on HP PCs.

InstallShield is used by 71,000 organizations, half of them independent software developers and the rest corporate network administrators seeking to ensure smooth software installation.

The Yahoo Toolbar will be an optional add-on that software developers using InstallShield may choose to include alongside their programs. Yahoo will pay Acresso an undisclosed amount for bringing in new Yahoo search users.

The Yahoo Toolbar is the first software to be featured in Acresso's new program to offer software makers a set of "value-added services." This allows them to supplement revenue they generate from sales of their own software by sharing in the proceeds from advertising revenue generated by Yahoo and other services that will eventually be part of the program.

Acresso chose Yahoo as its preferred Web search provider for that program, which delivers a wider range of software tools to Windows-based PC users, said David Rowley, Acresso's senior vice president of corporate development.

Acresso counts among its customers major software makers such as Microsoft, SAS, BMC Software (NYSE: BMC) and IBM (NYSE: IBM), as well as thousands of small software makers.

Macrovision spun off the 380-employee Chicago-based company to private equity firm Thomas Bravo in April. Acresso generated $113 million revenue in 2007 as part of Macrovision.